1. Field of the Invention
The present invention is directed to a control device associated with a movable member and which operates in such a manner that a specific position of the movable member such as a vehicular seat is memorized in a memory and even though the movable member is transferred to another position, the movable member can be returned to the specific position by means of an easy or simple switch operation.
2. Prior Art
In recent years, in vehicles, for establishing a suitable attitude of an occupant when he/she sits on a seat device, the seat device is configured so that its portions are transferred to specific positions depending on his/her outer profile and the set positions are fed, as signals, to a memory of a controller. When another occupant person sits on the seat device, sometimes the portions of the seat may be transferred to other positions for his/her own best attitude. Thereafter, if the occupant wants to sit on the seat device, when the occupant pushes a button of the controller, on the basis of the memorized set position signals, the controller moves the portions of the seat device to the respective set positions. Such a seat device, which is called a `memory seat`, is developed for relieving seat related adjusting efforts of the occupant when he/she gets in and/or out the vehicle.
As is well known, the seat device includes a seat-cushion, a seat-back hinged to a rear portion of the seat-cushion, and a head-rest mounted telescopically to a top portion of the seat-back. The seat device also includes a sliding motor, a reclining motor, a front-vertical motor, a rear-vertical motor, and a head-rest motor for moving the whole seat device in the vehicle-longitudinal direction, bringing the seat-back into a desired or reclined angular position, moving a front portion of the seat-cushion in the vertical direction, moving a rear portion of the seat-cushion in the vertical direction, and establishing telescopic movements of the head-rest relative to the seat-back, respectively. These motors are under the control of the controller. After the occupant brings these members to his/her favorite or suitable positions, the resultant positions are memorized. Even though position change is made relating to at least one of the seat-cushion per se, the front portion of the seat-cushion, the rear-portion of the seat-cushion, the seat-back, and the head-rest, when a restoration switch or button is turned on, the controller returns the member from another position to the set or memorized position by driving the corresponding motor.
In the foregoing structure, the current position of each member or portion is determined by a rotational condition of the corresponding motor, which requires a position sensor and related parts for each motor. In detail, for example, `NEW CAR FEATURES ON TOYOTA CROWN MAJESTA` issued on September, 1991 indicates, on its pages 5-64 and 5-65, that a shaft of the motor is provided with a magnet, a rotational condition of the magnet is detected by a hole element opposed to the magnet, and the resultant output from the hole element or the motor rotational signal is fed to the controller by way of a harness.
However, in the foregoing structure, each motor has to be provided therewith its own magnet, hole element, and wire harness, with the result that the sole seat device has to include a considerable number of parts. Providing such parts for the motor is very cumbersome and the surrounding area of the motor becomes very complex. In addition, since such an arrangement has to be provided for each of the other seats, the foregoing drawbacks are multiplied.